The chromic acid oxidation of aliphatic secondary alcohols—substituent effects and the mechanism

The mechanism of the chromic acid oxidation of a number of substituted propan-2-ols has been studied in aqueous acetic acid medium. Electron withdrawing substituents retard the reaction considerably while electron-releasing substituents accelerate the reaction. A good correlation exists between the rate and σ* values. The ρ* value is ?1.60. The results are interpreted in terms of a rate-determining abstraction of the secondary hydrogen as a hydride anion.